Re: [Elecraft] Digital mode power handling for KAT3
I agree that the KAT3(a) can run 100 watts for quite a while. I have run 100 watts in RTTY contests with both of my K3S(s) without issue. I have never used FT8, I am sure that my RTTY transmissions are shorter than a 13 second FT8 transmission however the non-transmit time in-between RTTY transmissions can be very short when CQing at times. I have no personal experience with the KAT3's power capability, I am sure that it depends on what it is matching. I have all OWA Yagis so I have no need for a tuner. John KK9A David Gilbert AB7E wrote: I am reasonably certain that the KAT3 can handle 100 watts for a lengthy period to time (enough for normal FT8 purposes) if the SWR it is trying to match is low enough. But the original query didn't say how high an SWR he was trying to match. The KAT3 is certainly capable of matching some pretty high SWRs (well over 10:1), but the question is how long can it push 100 watts into an SWR that it could otherwise normally handle at lower SWR. Another factor is the phase of the impedance the KAT3 is trying to match. A high SWR could present either a capacitive load or an inductive load to the KAT3. In one case it could result in high currents within the KAT3 ... in another it could mean high internal voltages. So the real question is ... can the KAT3 survive for X amount of time when pushing 100 watts into a high SWR at most any phase? I can pretty much guarantee that nobody knows the answer to that question. I wouldn't be at all surprised if the KAT3 could handle 100 watts into a high SWR for periods of time that were comfortable for FT8 if the phase of the load impedance resulted in higher currents. I'm not so confident about that if the phase gave high voltages. Heating takes a bit of time to be destructive ... voltage breakdowns and arc overs happen very quickly. 73, Dave AB7E __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Digital mode power handling for KAT3
__ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Digital mode power handling for KAT3
The answer is in the results of simple questions: Who, if any, has had their KAT3 fail and for what cause? What was actual (r,x,c) antenna load, that was being attempted? I suspect the failures are low, it's smart enough to quit trying if the match is too extreme. The same components (mostly) are used in the KAT500 (just larger sizes) which also has a low failure rate. Instead of guessing, answers of actual failures would provide data points. 73, Rick nk7i On 10/13/2023 11:56 AM, David Gilbert wrote: I am reasonably certain that the KAT3 can handle 100 watts for a lengthy period to time (enough for normal FT8 purposes) if the SWR it is trying to match is low enough. But the original query didn't say how high an SWR he was trying to match. The KAT3 is certainly capable of matching some pretty high SWRs (well over 10:1), but the question is how long can it push 100 watts into an SWR that it could otherwise normally handle at lower SWR. Another factor is the phase of the impedance the KAT3 is trying to match. A high SWR could present either a capacitive load or an inductive load to the KAT3. In one case it could result in high currents within the KAT3 ... in another it could mean high internal voltages. So the real question is ... can the KAT3 survive for X amount of time when pushing 100 watts into a high SWR at most any phase? I can pretty much guarantee that nobody knows the answer to that question. I wouldn't be at all surprised if the KAT3 could handle 100 watts into a high SWR for periods of time that were comfortable for FT8 if the phase of the load impedance resulted in higher currents. I'm not so confident about that if the phase gave high voltages. Heating takes a bit of time to be destructive ... voltage breakdowns and arc overs happen very quickly. 73, Dave AB7E On 10/13/2023 8:03 AM, Bill Frantz wrote: I have frequently used my K3 at 100 watts with FT8 and RTTY. I haven’t had anything which would indicate that components are getting overstressed (e.g. bad smells). Now, I don’t think I have given a full 100 watts when something isn’t connected in the antenna system, although the KAT3 does “match” an open antenna line. Since in that situation, it clicks for a long time before coming to a “match”, I tend to notice that there is a problem before applying full power. 73 Bill AE6JV On Oct 12, 2023, at 23:42, David Gilbert wrote: I thought I was clear, but apparently not. It is 100% duty cycle for 13 seconds, and zero for 2 + 15 seconds. "Duty cycle" is all a function of what period of time you choose to integrate over. Lots of components if heavily over stressed can go south in 13 seconds. Whether that is the case with the KAT3 is unspecified as far as I can tell. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rick.n...@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Digital mode power handling for KAT3
I am reasonably certain that the KAT3 can handle 100 watts for a lengthy period to time (enough for normal FT8 purposes) if the SWR it is trying to match is low enough. But the original query didn't say how high an SWR he was trying to match. The KAT3 is certainly capable of matching some pretty high SWRs (well over 10:1), but the question is how long can it push 100 watts into an SWR that it could otherwise normally handle at lower SWR. Another factor is the phase of the impedance the KAT3 is trying to match. A high SWR could present either a capacitive load or an inductive load to the KAT3. In one case it could result in high currents within the KAT3 ... in another it could mean high internal voltages. So the real question is ... can the KAT3 survive for X amount of time when pushing 100 watts into a high SWR at most any phase? I can pretty much guarantee that nobody knows the answer to that question. I wouldn't be at all surprised if the KAT3 could handle 100 watts into a high SWR for periods of time that were comfortable for FT8 if the phase of the load impedance resulted in higher currents. I'm not so confident about that if the phase gave high voltages. Heating takes a bit of time to be destructive ... voltage breakdowns and arc overs happen very quickly. 73, Dave AB7E On 10/13/2023 8:03 AM, Bill Frantz wrote: I have frequently used my K3 at 100 watts with FT8 and RTTY. I haven’t had anything which would indicate that components are getting overstressed (e.g. bad smells). Now, I don’t think I have given a full 100 watts when something isn’t connected in the antenna system, although the KAT3 does “match” an open antenna line. Since in that situation, it clicks for a long time before coming to a “match”, I tend to notice that there is a problem before applying full power. 73 Bill AE6JV On Oct 12, 2023, at 23:42, David Gilbert wrote: I thought I was clear, but apparently not. It is 100% duty cycle for 13 seconds, and zero for 2 + 15 seconds. "Duty cycle" is all a function of what period of time you choose to integrate over. Lots of components if heavily over stressed can go south in 13 seconds. Whether that is the case with the KAT3 is unspecified as far as I can tell. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Digital mode power handling for KAT3
__ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Digital mode power handling for KAT3
I have frequently used my K3 at 100 watts with FT8 and RTTY. I haven’t had anything which would indicate that components are getting overstressed (e.g. bad smells). Now, I don’t think I have given a full 100 watts when something isn’t connected in the antenna system, although the KAT3 does “match” an open antenna line. Since in that situation, it clicks for a long time before coming to a “match”, I tend to notice that there is a problem before applying full power. 73 Bill AE6JV > On Oct 12, 2023, at 23:42, David Gilbert wrote: > > I thought I was clear, but apparently not. It is 100% duty cycle for 13 > seconds, and zero for 2 + 15 seconds. "Duty cycle" is all a function of what > period of time you choose to integrate over. Lots of components if heavily > over stressed can go south in 13 seconds. Whether that is the case with the > KAT3 is unspecified as far as I can tell. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Digital mode power handling for KAT3
I thought I was clear, but apparently not. It is 100% duty cycle for 13 seconds, and zero for 2 + 15 seconds. "Duty cycle" is all a function of what period of time you choose to integrate over. Lots of components if heavily over stressed can go south in 13 seconds. Whether that is the case with the KAT3 is unspecified as far as I can tell. Dave AB7E On 10/12/2023 8:02 AM, Bob McGraw wrote: If I did my math correct, FT-8 is 46.42% duty cycle. 13+15 = 28. Therefore (13/28)*100= 46.42% 73 Bob, K4TAX On 10/12/2023 7:33 AM, elecraft-requ...@mailman.qth.net wrote: Message: 17 Date: Wed, 11 Oct 2023 21:40:19 -0700 From: David Gilbert To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Digital mode power handling for KAT3 Message-ID: <53d23883-e9e2-451d-cb5e-38e78b991...@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed FT8 is definitely full duty cycle for its 13 second transmit period, but of course then it is idle for the last two period and idle for the 15 seconds it is receiving. Dave?? AB7E __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to ab7e...@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Digital mode power handling for KAT3
FWIW: I use my K3/KAT3 at 100 W in RTTY contests with no issues.? % derating could be a function of the complex impedance at the end of your transmission line ... my match on all bands is not terrible. Be aware that the KAT3 has a IF trap (C10/L10) which may catastrophically fail depending on the frequency, power and antenna impedance. Recourse is to remove them (i.e. bypass) as the K3 doesn't need the trap and it is causing issues. On the KAT3A the trap is eliminated. Since you're planning higher duty cycles, you're more likely to run into this. Google "KAT3 C10 failure" for details. Geert Jan __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] Digital mode power handling for KAT3
If I did my math correct, FT-8 is 46.42% duty cycle. 13+15 = 28. Therefore (13/28)*100= 46.42% 73 Bob, K4TAX On 10/12/2023 7:33 AM, elecraft-requ...@mailman.qth.net wrote: Message: 17 Date: Wed, 11 Oct 2023 21:40:19 -0700 From: David Gilbert To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Digital mode power handling for KAT3 Message-ID: <53d23883-e9e2-451d-cb5e-38e78b991...@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed FT8 is definitely full duty cycle for its 13 second transmit period, but of course then it is idle for the last two period and idle for the 15 seconds it is receiving. Dave?? AB7E __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] Digital mode power handling for KAT3
Ken: I have a K3S with the internal tuner. I find no issues nor concerns in running 100 watts in any mode. Page 79 of the manual does not address any reduced power requirement other than operating with a 20:1 SWR (20 watts). 73 Bob, K4TAX On 10/12/2023 7:33 AM, elecraft-requ...@mailman.qth.net wrote: Message: 7 Date: Wed, 11 Oct 2023 12:50:38 -0400 From: To: Subject: [Elecraft] Digital mode power handling for KAT3 Message-ID: <06cf01d9fc63$10461310$30d23930$@gmail.com> Content-Type: text/plain; charset="us-ascii" Hello. I recently bought a very nice K3 from a friend. It has the KAT3 auto-tuner installed. Due to the duty cycle of most digital modes, most, if not all, external auto tuners are "de-rated" for digital modes. I haven't been able to find any reference to this for the KAT3. Does anyone know the power handling capability of the KAT3 for digital modes? Thanks in advance. 73, Ken, KJ9B __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Digital mode power handling for KAT3
Not really. He asked about the KAT3, not the K3. The KAT3 can handle some very wide impedances, but the question is can it handle full power from the K3 when it sees a high SWR at the output. For example, how much power can the KAT3 handle for 10 minutes when trying to match an SWR of 10:1? Maybe it can handle 100 watts for 10 minutes at that kind of SWR, but I can't find any spec that says so. The KAT3 manual is an assembly manual only. Dave AB7E On 10/11/2023 10:04 PM, Mark Musick wrote: From the K3 and K3S manuals: Duty Cycle CW and SSB modes, 100% 10-min. 100W key-down at 25 C ambient I think this answers the question. 73, Mark, WB9CIF -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of ken.k...@gmail.com Sent: Wednesday, October 11, 2023 16:51 To: elecraft@mailman.qth.net Subject: [Elecraft] Digital mode power handling for KAT3 Hello. I recently bought a very nice K3 from a friend. It has the KAT3 auto-tuner installed. Due to the duty cycle of most digital modes, most, if not all, external auto tuners are "de-rated" for digital modes. I haven't been able to find any reference to this for the KAT3. Does anyone know the power handling capability of the KAT3 for digital modes? Thanks in advance. 73, Ken, KJ9B __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Digital mode power handling for KAT3
>From the K3 and K3S manuals: Duty Cycle CW and SSB modes, 100% 10-min. 100W key-down at 25 C ambient I think this answers the question. 73, Mark, WB9CIF -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of ken.k...@gmail.com Sent: Wednesday, October 11, 2023 16:51 To: elecraft@mailman.qth.net Subject: [Elecraft] Digital mode power handling for KAT3 Hello. I recently bought a very nice K3 from a friend. It has the KAT3 auto-tuner installed. Due to the duty cycle of most digital modes, most, if not all, external auto tuners are "de-rated" for digital modes. I haven't been able to find any reference to this for the KAT3. Does anyone know the power handling capability of the KAT3 for digital modes? Thanks in advance. 73, Ken, KJ9B __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net/ Please help support this email list: http://www.qsl.net/donate.html Message delivered to markmus...@outlook.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Digital mode power handling for KAT3
FT8 is definitely full duty cycle for its 13 second transmit period, but of course then it is idle for the last two period and idle for the 15 seconds it is receiving. Dave AB7E On 10/11/2023 8:20 PM, Ken WA8JXM wrote: Not just the tuner, the K3 is not rated for full power on 100% duty cycle modes. Just like it's not rated or 100% key down CW. But realize that many of the modes are half transmit and half listen. Different digital modes have different duty cycles. From the W1HKJ.com website: 100% duty cycle: Olivia, MFSK,RTTY 80%: BPSK, MT63 44% CW 22%:FieldHell There are more modes on Dave's website, but those are some of the major ones. IDK if Joe Taylor has similar information on his website for the modes he supports. It loioks like his modes may require full duty cycle. Ken __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Digital mode power handling for KAT3
Not just the tuner, the K3 is not rated for full power on 100% duty cycle modes. Just like it's not rated or 100% key down CW. But realize that many of the modes are half transmit and half listen. Different digital modes have different duty cycles. From the W1HKJ.com website: 100% duty cycle: Olivia, MFSK,RTTY 80%: BPSK, MT63 44% CW 22%:FieldHell There are more modes on Dave's website, but those are some of the major ones. IDK if Joe Taylor has similar information on his website for the modes he supports. It loioks like his modes may require full duty cycle. Ken On Wed, Oct 11, 2023 at 12:51 PM wrote: > Hello. I recently bought a very nice K3 from a friend. It has the KAT3 > auto-tuner installed. Due to the duty cycle of most digital modes, most, > if > not all, external auto tuners are "de-rated" for digital modes. I haven't > been able to find any reference to this for the KAT3. Does anyone know the > power handling capability of the KAT3 for digital modes? > > Thanks in advance. > > 73, > Ken, KJ9B > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to wa8...@gmail.com > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Digital mode power handling for KAT3
FWIW: I use my K3/KAT3 at 100 W in RTTY contests with no issues. % derating could be a function of the complex impedance at the end of your transmission line ... my match on all bands is not terrible. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County ken.k...@gmail.com wrote on 10/11/2023 9:50 AM: Hello. I recently bought a very nice K3 from a friend. It has the KAT3 auto-tuner installed. Due to the duty cycle of most digital modes, most, if not all, external auto tuners are "de-rated" for digital modes. I haven't been able to find any reference to this for the KAT3. Does anyone know the power handling capability of the KAT3 for digital modes? Thanks in advance. 73, Ken, KJ9B -- This email has been checked for viruses by AVG antivirus software. www.avg.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] Digital mode power handling for KAT3
Hello. I recently bought a very nice K3 from a friend. It has the KAT3 auto-tuner installed. Due to the duty cycle of most digital modes, most, if not all, external auto tuners are "de-rated" for digital modes. I haven't been able to find any reference to this for the KAT3. Does anyone know the power handling capability of the KAT3 for digital modes? Thanks in advance. 73, Ken, KJ9B __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
